Dental Tribune Indian Edition

3Dental Tribune Indian Edition - April 2013 Dental occlusion/temporomandibular joint and general body health Clinical evidence and mechanism of an underestimated relationship Trends & Applications Published by Jaypee Brothers Medical Publishers (P) Ltd., India © 2013, Dental Tribune International GmbH. All rights reserved. Dental Tribune India makes every effort to report clinical information and manufacturer’s product news accurately, but cannot assume responsibility for the validity of product claims, or for typographical errors. The publishers also do not assume responsibility for product names or claims, or statements made by advertisers. Opinions expressed by authors are their own and may not reflect those of Dental Tribune International. Chairman DT India Jitendar P Vij jaypee@jaypeebrothers.com Director P N Venkatraman venkatraman@jaypeebrothers.com Dental Tribune India Published by: Jaypee Brothers Medical Publishers (P) Ltd. 4838/24, Ansari Road, Daryaganj New Delhi 110002, India Phone: +91 11 43574357 Email: jaypee@jaypeebrothers.com Website: www.jaypeebrothers.com dental tribune Indian Edition International Imprint Licensing by Dental Tribune International Publisher Torsten Oemus Group Editor Daniel Zimmermann newsroom@dental-tribune.com +49 341 48 474 107 Clinical Editor Magda Wojtkiewicz Online Editors Yvonne Bachmann Claudia Duschek Copy Editors Sabrina Raaff Hans Motschmann Publisher/President/CEO Torsten Oemus Director of Finance & Controlling Dan Wunderlich Media Sales Managers Matthias Diessner Peter Witteczek Maria Kaiser Melissa Brown Weridiana Mageswki Hélène Carpentier Marketing & Sales Services Esther Wodarski Nasrin Gazawi License Inquiries Jörg Warschat Accounting Karen Hamatschek Business Development Manager Claudia Duschek Executive Producer Gernot Meyer International Editorial Board Dr Nasser Barghi, USA – Ceramics Dr Karl Behr, Germany – Endodontics Dr George Freedman, Canada – Aesthetics Dr Howard Glazer, USA – Cariology Prof Dr I. Krejci, Switzerland – Conservative Dentistry Dr Edward Lynch, Ireland – Restorative Dr Ziv Mazor, Israel – Implantology Prof Dr Georg Meyer, Germany – Restorative Prof Dr Rudolph Slavicek, Austria – Function Dr Marius Steigmann, Germany – Implantology © 2013, Dental Tribune International GmbH. All rights reserved. Dental Tribune makes every effort to report clinical information and manufacturer’s product news accurately, but cannot assume responsibility for the validity of product claims, or for typographical errors. The publishers also do not assume responsibility for product names or claims, or statements made by advertisers. Opinions expressed by authors are their own and may not reflect those of Dental Tribune International. Dental Tribune International Holbeinstr. 29, 04229 Leipzig, Germany Tel.:+4934148474302|Fax:+4934148474173 www.dental-tribune.com | info@dental-tribune.com Regional Offices Asia Pacific Dental Tribune Asia Pacific Limited Room A, 20/F, Harvard Commercial Building, 111 Thomson Road, Wanchai, Hong Kong Tel.: +852 3113 6177 | Fax +8523113 6199 The Americas Tribune America 116 West 23rd Street, Ste. 500, NewYork, N.Y. 10011, USA Tel.: +1 212 244 7181 | Fax: +1 212 224 7185 Drs Yong­Keun Lee & Hyung­Joo Moon South Korea During the treatment of symptoms originating from disorders of the tem­ poromandibular joint (TMJ) and oc­ clusion, it was found that restoring the TMJ to its normal condition resulted in a change of general body health. In most cases, the change of health was for the better. Owing to similar reports, a connection between TMJ status and general body health was therefore hypothesized. However, the mechanism of this relationship remains unclear. In this article, the relationships between dental occlusion/TMJ status and general body health are reviewed with reference to peer­reviewed papers. A conceptual theory is propo­ sed that may explain this mechanism. TMJ and myofascial pain Dental occlusion is the relationship between the maxillary and mandi­ bular teeth when they approach each other.1 The TMJ is the joint of the jaw, which is unique in that it is the only bilateral joint that crosses the midli­ ne.2 As the treatment of dental dise­ ases aims to achieve harmony within the entire stomatognathic system, te­ eth could be literally considered to be a set of gears anchored in bone, while the upper and lower jaws are attached to each other by the TMJ.3 The causes of TMJ disorders can be divided into five categories: dental, trauma, lifestyle habits, stressful so­ cial situations, and emotional factors.4 Trauma can be in the form of whiplash, traction appliances, and blows to the head, face, or jaw.4 Evidence of sig­ nificant trauma to the TMJ has also been found following hyperextension of the cervical spine.5 With regard to habits, bad posture, bad ergonomics at work, oral and childhood habits, as well as poor diet and strenuous activities such as heavy lifting, have been cited.4 Myofascial pain, deriving from the hyperalgesic trigger points located in skeletal muscle and fascia, is com­ monly characterized by persistent regional pain.6 The myofascial compo­ nent has generally been considered to be part of pain syndromes that invol­ ve TMJ. Trigger points in masticatory muscles are presumably caused by ma­ locclusion, misalignment and habitual para­function of the jaws, abnormal head and neck postures, or trauma.6 Relationship between TMJ and general body health There have been several studies on the relationship between occlusion/ TMJ and general body health. Among other findings, it has been found that lesions in the masticatory muscles or dento­alveolar ligaments can perturb visual stability and thus generate po­ stural imbalance.7 The position and functioning of the mandible also have an effect on the centre of gravity.8,9 Dental occlusion is associated with reduced lower extremity strength, agi­ lity and balance in elderly people.10 The proper functional occlusion of na­ tural or artificial teeth has been shown to play an important role in genera­ ting an adequate postural reflex.10 The subgroups of general body conditions associated with TMJ may be divided into the following three categories: 1) Synchronisation of the head and jaw muscles with other muscles There is a necessary systematic synchronisation of the head and jaw muscles with the other muscles of the body to maintain proper body po­ sture. The functional coupling of the stomatognathic system with the neck muscles is well known. Patients suf­ fering from occlusal or TMJ disorders have frequently reported dysfunction and pain in their neck muscles.12,13 An imbalance of sternocleidomastoid muscle activity, often leading to neck pain, can be induced by a unilateral loss of occlusal support.14 The biomechanical impact on cer­ vical vertebrae during mastication has been calculated, which confirmed that vertical occlusal alteration can in­ fluence stress distribution in the cer­ vical column.15 Possible associations between trunk and cervical asymme­ try and facial symmetry have been reported.16 For example, it has been found that visual perception control is most important in orienting the head in the frontal plane.16 A relationship between dental occlusion and postu­ ral control has also been postulated.17 2) TMJ and body stability Dental occlusion/TMJ condi­ tion exerts an influence on body stability. Human beings assume a relatively unstable postural state when in the standing position; the­ refore, the maintenance of a stan­ ding position is related to fluctua­ tion in the centre of gravity, which is controlled by information from the ocular region, the three semicircu­ lar canals and anti­gravity muscles.18 It has been suggested that occlusion and head position affect the centre of gravity, resulting in an increased risk of falling when abnormal.19 Poor or absent dental occlusion may decrease proprioception in this area, interfe­ ring with the proper stability of the head posture.7 It is thought that tooth loss is a risk factor for postural insta­ bility.20 Physiologically, mechanical receptors in the periodontal mem­ brane control mandibular movements and coordinate masticatory fun­ ction,21 and this is related to the motor activity of the neck muscles.22 Fluctuation in the centre of gra­ vity caused by altering the occlusal contact area experimentally was exa­ mined experimentally, and the re­ sults confirmed that occlusal contact affects gravity fluctuation and that ap­ propriate occlusion attained by main­ taining even occlusal contact in the posterior region is crucial for gravity fluctuation.23 3) TMJ and physical performance TMJ conditions can influence physical performance. Trainers of­ ten advise athletes to wear occlusal splints or mouth guards during com­ petitions in order to increase motor performance.24 It has also been repor­ ted that proper teeth clenching plays an effective role in the enhancement of physical performance.25 The relationship between the pre­ sence of occlusal support in edentulous subjects and their capacity for physical exercise has been investigated, and it was concluded that reconstruction of occlusal support holds significance not only for the restoration of masticatory function but also for the maintenance of physical exercise.26 Mechanism of relationship between the TMJ and general body health based on the myofascial aspect It is the first hypothesis of this ar­ ticle that TMJ and other parts of the body are connected through fasciae, which is a connective element betwe­ en various anatomical structures,27 very similar to a three­dimensional network extending throughout the whole body.28,29 This network can be stretched by the contraction of un­ derlying muscles and transmit tension over a distance.30,31 The fascial tissues are arranged vertically, from head to toe, and four interconnected transverse fa­ scial planes criss­cross the body. Therefore, should an injury occur in one part of the body, pain and dysfunction may occur throughout the body.32 Mechanism based on qi and the meridian aspect The second hypothesis is that the TMJ and other parts of the body are connected through the meridian system, which is constituted of the fasciae. “...lesions in the masticatory muscles or dento- alveolar ligaments can perturb visual stability.” → DT page 4